The present invention relates in general to a headset for receiving both FM and AM communication signals and in particular to a headset which receives FM signals in one earphone and AM signals in the other earphone with a microphone and first and second switches for enabling the user to selectively transmit a response on either the FM channel or the AM channel.
It is well known in certain occupational fields that individuals such as, for example, police officers or control tower operators or firemen or snow removal equipment operators must communicate with two different systems operating on AM and FM frequencies respectively. For example, airport firemen or snow removal equipment operators may communicate with the control tower on an AM frequency while at the same time maintaining communications with airport operations on an FM frequency. With the presently existing systems, the FM and AM signals may terminate at speakers mounted in a vehicle having high noise levels such as a snow plow or fire engine and when the signals are received, it is often difficult to tell which circuit was operative, the FM or the AM circuit. This difficulty arises normally because of the noise level of the environment in which the communication system is used.
The present invention overcomes the disadvantages of the prior art by providing a headset which receives only the FM signals in one ear and only the AM signals in the other ear. Thus, there is no doubt as to when a message has been received on either the AM or FM circuits. To transmit a response or reply to the sender of the received signal, the user simply presses a switch representing FM if the response is to an FM signal and speaks into the microphone and the reply is transmitted on the FM circuit. If the signal received were an AM signal, then the user simply depresses an AM switch and speaks and the reply is transmitted on the AM circuit.
In the preferred embodiments, an FM transmit switch is placed on the FM earphone and an AM transmit switch is placed on the AM earphone so that when the operator desires to answer the message received in a particular earphone, he simply depresses the switch actually physically positioned on that earphone and speaks and the reply is transmitted to that particular circuit whether it is AM or FM.
Thus, it is an object of the present invention to provide a new and improved communications headset which receives only the AM signals in one earphone and only the FM signals in the other earphone and which has a common microphone whose output is coupled to either the AM or FM circuit by depressing the proper switch.
It is also an object of the present invention to avoid the confusion that is caused by noise levels associated with the prior art devices by coupling the FM signals to one earphone only and the AM signals to the other earphone only and physically mounting a transmission switch on each earphone so that in order to respond to a message received in one particular earphone the user simply depresses or actuates the switch physically positioned on that earphone and speaks into the microphone.